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PublishMarilyn Terry Modified over 8 years ago
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'Some people would rather die than think and usually do'. Bertrand Russell 'If we always do what we've always done, we will get what we've always got.' Adam Urbanski
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WEATHER IS THE MOVEMENT OF AIR MASSES DRIVEN BY THE SUN. EACH OF THESE AIR MASSES ARE AT DIFFERENT TEMPERATURES AND CONTAIN DIFFERENT AMOUNTS OF MOISTURE. ONE AIR MASS WILL INFLUENCE AND BE INFLUENCED BY OTHER AIR MASSES. IT IS A VERY COMPLEX SYSTEM. SO COMPLEX THAT CHAOS THEORY TALKS ABOUT THE “BUTTERFLY EFFECT.”
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ALL WEATHER TAKES PLACE IN THE TROPOSPHERE. THE TROPOSPHERE IS 10 TO 14 KM HIGH. IT CONTAINS ABOUT 75% OF THE MASS OF THE ATMOSPHERE AND 99% OF THE WATER VAPOR. THE SUN PROVIDES THE ENERGY. BUT THE CAUSE IS UNEVEN HEATING OF THE EARTH’S SURFACE. THE SURFACE IS HEATED UNEVENLY FOR THREE REASONS: 1.TILT OF THE EARTH ON ITS AXIS. 2.NIGHT ON ONE SIDE AND DAY ON THE OTHER. 3.DIFFERENT SURFACE MATERIALS HEAT AT DIFFERENT RATES.
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THIS ENERGY IS NOT EQUALLY DISTRIBUTED OVER THE SURFACE OF THE EARTH. THE EARTH’S AXIS IS TILTED AT 23.5 o RELATIVE TO OUR ORBIT ABOUT THE SUN.
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THIS GIVES US OUR SEASONS.
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DIFFERENTIAL HEATING ALSO LEADS TO WINDS AND WIND PATTERNS ON BOTH A LOCAL AND A GLOBAL LEVEL.
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CORIOLIS EFFECT CAUSES WINDS TO BEND TO THE RIGHT IN THE NORTHEN HEMISPHERE AND TO THE LEFT IN THE SOUTHERN HEMISPHERE.
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WHAT IS THE ATMOSPHERE? THE LAYER OF GASES SURROUNDING THE EARTH AND HELD BY GRAVITY. THE ATMOSPHERE SUPPORTS LIFE ON EARTH. IT ABSORBS SOLAR RADIATION. IT PROTECTS US FROM HIGH ENERGY RADIATION AND THE FRIGID VACUUM OF OUTER SPACE. IT TRANSFERS HEAT FROM WARM AREAS TO COLDER AREAS. NOTE: IT’S NOT VERY THICK. IF YOU HAD A CAR THAT WOULD GO STRAIGHT UP, YOU COULD BE IN SPACE IN AN HOUR.
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THE COMPOSITION OF THE ATMOSPHERE IS: 78% NITROGEN 21%OXYGEN 1%ARGON 0.038% CARBON DIOXIDE THIS COMPOSITION IS KEPT IN BALANCE BY LIFE ON EARTH. IT HAS VARIED OVER GEOLOGIC TIME.
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OTHER IMPORTANT GASES ARE WATER VAPOR AND OZONE. THE AMOUNT OF WATER VAPOR WILL VARY WITH TEMPERATURE. AS THE TEMPERATURE INCREASES, THE AIR CAN HOLD MORE WATER VAPOR.
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THE NORMAL MOLECULAR FORM OF OXYGEN IS O 2. OZONE IS A LESS STABLE FORM OF OXYGEN, AND ITS FORMULA IS O 3. IN THE STRATOSPHERE, OZONE ABSORBS HARMFUL UV RADIATION. IF THE OZONE LAYER DID NOT EXIST, LIFE AS WE KNOW IT COULD NOT EXIST. HOWEVER, OZONE IS VERY REACTIVE. OZONE AT GROUND LEVEL IS DANGEROUS.
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LAYERS OF THE ATMOSPHERE BASED ON HOW THE TEMPERATURE CHANGES, THE ATMOSPHERE IS DIVIDED INTO LAYERS.
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TROPOSPHERE - 75% OF THE MASS OF THE ATMOSPHERE IS IN THE TROPOSPHERE. IT EXTENDS FROM EARTH’S SURFACE UP TO ABOUT 10 KM. ABOVE THIS IS A LAYER WHERE THE TEMPERATURE IS RELATIVELY CONSTANT - THE TROPOPAUSE. THE JET STREAM, A FAST MOVING WIND CURRENT, OCCURS IN THE TROPOPAUSE. THE STRATOSPHERE IS THE LAYER ABOVE THE TROPOPAUSE. THE OZONE LAYER IS IN THE STRATOSPHERE, WHICH CAUSES THE TEMPERATURE INCREASE.
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THE STRATOSPHERE EXTENDS UP TO ABOUT 50 KM. ABOVE THE STRATOSPHERE IS A THIN LAYER CALLED THE STRATOPAUSE WHERE THE TEMPERATURE IS CONSTANT. ABOVE THIS IS THE MESOSPHERE, WHERE THE TEMPERATURE DECREASES AGAIN TO -100 o C. THIS IS BECAUSE THERE IS NO CONCENTRATED LAYER OF OXONE. THE MESOSPHERE GOES FROM ABOUT 50 KM UP TO 80 KM. METEOROIDS USUALLY BURN UP IN THIS LAYER.
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THE THERMOSPHERE IS ABOVE THE MESOPAUSE. IN THIS LAYER, THE AIR HEATS UP BECAUSE OF RADIATION. THIS LAYER GOES FROM 80 KM UP. IT CONTAINS THE MAGNETOSPHERE - EARTH’S MAGNETIC FIELD. THE AURORAS OCCUR HERE.
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Earth’s atmosphere exerts pressure on us. At sea level, the pressure is 14.7 lb/in 2. It is due to the force of gravity on the column of air above us. Why don’t we notice it?
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IF YOU WERE ON A MOUNTAIN, WOULD THE WEIGHT OF THE AIR ABOVE YOU (AIR PRESSURE) BE GREATER THAN OR LESS THAN IT IS NOW?
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PRESSURE = FORCE (weight) / AREA OUR UNITS ARE USUALLY: POUNDS / IN. 2 (pounds per square inch) Or MILLIBARS Or INCHES OF MERCURY 1 ATMOSPHERE (pressure at sea level) = 14.7 psi = 1013.25 millibars = 760 mmHg = 29.92 in Hg
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A BAROMETER IS USED TO MEASURE AIR PRESSURE.
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SATELLITE DISTANCES – 200 TO 500 MILES - GEOSYNCHRONOUS AT 23,000 MI - HUBBLE SPACE TELESCOPE, 600 MI
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